Pressure relief valve for drug delivery device

Abstract

A drug delivery device includes a housing releasably coupled with a patient, a pressure chamber disposed in the housing and including a vent, a container at least partially disposed in the pressure chamber for storing a drug connectable in fluid communication with a fluid conduit, an activation mechanism, and a relief mechanism. The activation mechanism releases a pressurized drive fluid into the pressure chamber for expelling the drug from the container into the fluid conduit. The relief mechanism is operably coupled to the fluid conduit and is adapted to open the vent to release the drive fluid from the pressure chamber in response to a predetermined condition.

What is claimed is: 
     
         1 . A drug delivery device comprising:
 a housing adapted to be releasably coupled with a patient;   a pressure chamber disposed in the housing and including a vent;   a container at least partially disposed in the pressure chamber for storing a drug and connectable in fluid communication with a fluid conduit;   an activation mechanism adapted to release a pressurized drive fluid into the pressure chamber for expelling the drug from the container into the fluid conduit; and   a relief mechanism operably coupled to the fluid conduit and adapted to open the vent to release the pressurized drive fluid from the pressure chamber in response to a change in pressure in the fluid conduit,   wherein the relief mechanism includes a relief chamber having a first end and a second end, the relief chamber being operably coupled to the fluid conduit and including a movable member movable between the first end and the second end of the relief chamber and being biased towards the first end of the relief chamber,   wherein upon engaging the activation mechanism, the drug in the fluid conduit urges the movable member from the first end of the relief chamber to the second end of the relief chamber to operably couple the relief mechanism to the vent.   
     
     
         2 . The drug delivery device of  claim 1 , further comprising a resilient member coupled to the movable member to bias the movable member towards the first end of the relief chamber. 
     
     
         3 . The drug delivery device of  claim 1 , wherein upon completion of delivery of the drug, the movable member moves towards the first end of the relief chamber and opens the vent to remove the pressurized drive fluid from the pressure chamber. 
     
     
         4 . The drug delivery device of  claim 1 , further comprising an insertion mechanism configured to be operably connected and in fluid communication with the container via the fluid conduit, the insertion mechanism including at least one of a needle or a cannula to be inserted into the patient for delivering the drug to the patient. 
     
     
         5 . The drug delivery device of  claim 1 , further comprising a container access mechanism at least partially disposed within the housing and being operably coupled to at least one of the pressure chamber or the container, the container access mechanism comprising:
 a needle or a cannula; and   a sterile barrier disposed proximal to the needle or cannula in a first configuration where the sterile barrier is intact.   
     
     
         6 . The drug delivery device of  claim 5 , wherein upon engaging the activation mechanism, relative movement between the needle or cannula and the sterile barrier causes the needle or cannula to pierce the sterile barrier to create the fluid conduit allowing the drug to be expelled from the container. 
     
     
         7 . The drug delivery device of  claim 1 , further comprising an overpressure relief mechanism operably coupled to the relief mechanism to release the pressurized drive fluid from the pressure chamber when a pressure within the pressure chamber exceeds a predetermined value, wherein the overpressure relief mechanism optionally includes a resilient member adapted to exert an opposing force on the vent. 
     
     
         8 . The drug delivery device of  claim 1 , wherein the movable member comprises at least one of a fluid piston or a diaphragm. 
     
     
         9 . The drug delivery device of  claim 1 , wherein the pressurized drive fluid comprises at least one of a pressurized gas or a pressurized liquid.